Objectives: (1) Develop and apply new and improved techniques for analyzing oxidative metabolism of the cat brain and correlating these results to simultaneous extracellular potassium kinetic measurements. (2) Determine the Q10 of potassium kinetics in the cat hippocampus. (3) Validate oxidative metabolism measurements obtained by NADH fluorescence techniques with direct measurement of cortical oxygen consumption. Methods employed: a. NADH fluorescence measurements are made with a unique two-channel fluoremeter. b. Q10 measurements are made by cooling the brain with an "Elliott's B" solution drip while measuring local temperature with a thermistor. Potassium kinetics are measured with a potassium sensitive microelectrode following electrical stimulation. c. Cortical oxygen consumption is determined from the combination of oximetry and flow of blood drained from the sagittal sinus of cats. Major findings: (1) Clearance of potassium following stimulation of the brain is an exponential process. (2) The Q10 for this clearance is approximately 2.1. (3) A linear relationship exists between the amount of potassium released following a stimulus to the brain and the time integral of the NADH fluorescence signal. (4) NADH fluorescence signals appear to be related to direct oxygen consumption measurements. Singificance: Evidence for potassium clearance being an active process has been reinforced. The utility of NADH fluorescence as an indicator of oxidative metabolism has been demonstrated. Proposed course: Refinement and extension of work done to date.